1. Field of the Invention
The invention herein relates to a viscosity-adjusted surfactant concentrate composition, particularly to a flowable, pumpable, stable surfactant concentrate consisting essentially of a mixture of an alkylpolyglycoside surfactant, an anionic or amphoteric surfactant and an effective amount of a viscosity-adjusting agent.
As indicated in U.S. Ser. No. 07/406,992 noted above, anionic surfactants and amphoteric surfactants are known materials. In a manufacturing or shipping operation it is desirable in handling the surfactants that they be flowable, pumpable and stable at a viscosity to avoid difficulty in processing or shipping the compositions. However, at high concentrations of the anionic or amphoteric surfactants (above 25, and higher, 30 or 40% to about 80% concentrations by weight in water) the viscosity rapidly increases and forms gels. Accordingly, it has been necessary to provide low viscosities for processing and shipping that the solutions of the anionic or amphoteric surfactant be very dilute or have added thereto, agents which reduce the viscosity. Very dilute solutions are objectionable and undesirable from a shipping standpoint, as a large amount of water results in high freight and shipping costs which must be borne by the customer.
It is accordingly important and desirable that a means be provided for preparing highly concentrated compositions in water of anionic or amphoteric surfactants which are flowable, pumpable, pourable and stable on storage.
2. Statement of Related Art
Alcohols, such as ethanol, have been employed in attempts to reduce the viscosity. However, alcohols introduce a flammability problem requiring additional precautions and care in handling.
U.S. Pat. No. 4,488,981 discloses that the addition of alkyl mono and polyglucosides having alkyl groups with six (6) carbon atoms or less in the alkyl group, to aqueous liquid detergents mixtures of anionic or anionic and nonionic surfactants in water reduces the viscosity of the mixture. The patent discloses in Table III, that highly viscous, unpourable gels are obtained in water with no additive and also illustrates the use of ethyl alcohol to provide a highly fluid, easily pourable detergent. With a higher alkyl (8 to 20 carbon) polyglycoside the mass remains a highly viscous, unpourable mass. The anionic surfactants include the sulfates, sulfonates, carboxylates and phosphates, while the nonionic surfactants are the ethoxylated alcohols, phenols, carboxylic esters or amides.
It is also known that the addition of alkylpolyglycosides to a phosphate-built aqueous crutcher slurry can reduce the viscosity of the slurry (U.S. Pat. No. 4,675,127). U.S. patent application Ser. No. 07/260,646 discloses that the addition of an alkylpolyglycoside and an alkali metal chloride to a carbonate containing crutcher slurry, reduces the viscosity of the slurry. A crutcher slurry is a mixture containing minor amounts of surfactant materials and large amounts of detergent builders and fillers. Thus, a crutcher slurry is not a concentrate consisting essentially of surfactants, but rather a slurry of particulate material comprising anionic surfactants, builders, fillers and other solid materials which are used in detergent formulations.
On the other hand, U.S. Pat. No. 4,732,696 describes that the addition of an alkyl glycoside and ammonium chloride to an aqueous liquid detergent formulation can increase the viscosity of the formulation. U.S. patent application Ser. No. 07/353,723 discloses that the addition of an alkylpolyglycoside and an alkali metal chloride within a critical range increases the viscosity of certain liquid sulfosuccinate detergent compositions.
Another patent describing an increase in viscosity is U.S. Pat. No. 4,668,422. The patent deals with liquid hand-soap or bubble bath compositions and illustrates the viscosifying effect (viscosity increase) of the addition of a small amount of ammonium chloride to a mixture containing an alkylpolyglycoside, a betaine, and a fatty amine oxide or fatty amide in a composition which contains a water content preferably from about 70 to about 95% with a total solids or non-volatile content of about 5 to about 30, preferably 10 to 20%.
U.S. Pat. No. 4,839,098, discloses a liquid dishwashing detergent consisting essentially of a dialkyl sulfosuccinate and an alkyl glucoside. Viscosity regulators are mentioned generally which include urea, sodium chloride, ammonium chloride, magnesium chloride and sodium citrate, without discussion of the effect thereof. Each of the examples include a substantial amount of an alcohol, such as isopropanol or ethanol, which as noted earlier, has been used to reduce viscosity.
U.S. Pat. No. 3,954,679 describes the use of water-soluble inorganic salts, such as sodium chloride, for viscosity reduction of an alpha-olefin sulfonate detergent composition. At column 13, lines 40-45, the liquid detergents are made thinning the crutcher mix further with an aqueous alcoholic medium (equal parts of ethanol and water) and further including a hydrotrope such as sodium cumene sulfonate. In Example 3 a variety of materials are discussed to be used instead of the halide salt, some of which increase and some of which decrease the viscosity or have little effect on the gelation or viscosity characteristics.
In view of the foregoing, the art described above shows that the addition of materials, such as sodium chloride, is unpredictable. In some cases, dependent on the specific surfactants, end-use applications, other materials required, and the like, the material is used to increase the viscosity and in other circumstances to decrease the viscosity.